1. Field of the Invention
The present invention is a medical device. In particular it is a device for sealing the screw holes in an acetabular cup.
2. State of the Art
Total hip replacement often requires replacement of a patient's acetabulum with an acetabular cup prosthesis. Acetabular reamers remove pelvic bone to create a properly sized region on the pelvis to receive the acetabular cup and liner. Typically, a surgeon uses hemispherical reamers until a chosen acetabular cup-receiving shell can seat. One such shell is part of the ATH System of Kinamed, Inc. of Newbury Park, Calif., assignee of this application. In some patients, the shell can be cemented to the pelvic bone, in others it may be press fit, however, many patients have insufficient bone to secure the shell. For those latter patients, the shell is screwed into the pelvis through screw holes in the shell.
Orthopedic surgeons have become concerned about the impact of ultra-high molecular weight polyethylene (UHMWPE) wear debris that may cause osteolytic changes within the patient's bone. It is thought that the screw holes may allow the potentially destructive particles to come into contact with bone and cause damage by virtue of the cellular reaction to the wear debris material.